Manually-supported power tool



Feb. 17, 1931. A. H. COLLINS MANUALLY SUPPORTED POWER TOOL OriginalFiled April 3. 1928 6 a z 1 W o 3 2 M 7. 0 u 9 M A y a a fl$fgfl J 1 w e5 FL x R? s N W z, 4 .2 P 0/0 20/, z 4 7 6 7 Z 3 a M E 5 0. 8 5 A bPatented Feb. 17, 1931 a U -Iran STATES PATENT orricr; j

an'rnomr-n. counts, or. BRONXVILLE, NEW roux; Assmnoa 'ro omeaeo PNEU-IA'I'IC r001. courm,-or nnwyoax, n. Y., A conroaariou or NEW annsnyANUALm -SUProBTEn rowan. root? Application filed April}; 1928, SerialNo.- 286;985. Renewed August 4, 1930.

' This invention relates to portable power,

; operated percussive tools adapted to be manually supported anddirected to the work. It has practical application to tools for hand 5drilling and demolition work generally.

i One object of the invention is to relieve the operator so far aspossible of the sh ck and reaction of the tool when in operat on.Another object is to protect the percussion motor 10 of such a tool fromthe destructive efiorts of vibration. Other objects will be apparentfrom the detailed description which ollows:

In order to illustrate the invention one concrete embodiment thereof isshown in the '1 accompanying drawings in which:

Fig 1 is a vertical sectional view through the handle support andretainer portion of the tool showing the percusslve motor also partiallyin vertical section, the parts being no in the inoperative or non-runnmgpos1t1on of themotorfand Q p Fig. 2 is a view similarto Fig. 1 showingthe parts in the running posltlon of tl1e motor.

'In the embodiment of the invention chosen for-the purpose ofillustration, the tool comprises a cylinder 3 having an elongate axlalchamber 3a in which is mounted for hunted movement a percussive motor A,preferably of the fluid pressure type.. Cylinder 3 is arranged to bemanually supported by aligned handles 4 which in the present instanceare shown as forming part of a T head 5 which is secured to cylinder 3in any suitable manner as by bolts (not shown). Since motor is indicatedas of the fluid pressure type, head 5 preferably provides a connectionat 6 for metive fluid and a throttle valve at 7,'wh1ch 1s controlled bya lever 8 conveniently arranged adjacent handles 4, the pressue fluidreleased by the throttle valve being directed into the rearward orhandle end of chamber 311.

' Motor A has a head 9 slidably fitting the interior of chamber 3 andalso has a reduced 45 portion or barrel 10 whichextends beyond cylinder3, suitable supporting and packing means being provided on the cylinderincluding packing ring 171, packing 12, and gland nut 13. Within thepiston chamber of motor 7 A reciprocates a hammer piston 14' which iscontrolled by an automatically throviin sleeve valye 15 moving in timedrelation with the piston within a valve box 16 providedwith a cap 17held in place by a backhead 18, the latter having bores 18a therethroughto admit motive fluid from the rear emYof chamber- 3a to the motor.Packings 18 and 20 are arranged at opposite endsofmotQr head-Q andintermediate these packings vtlie head is reduced by an annular grooveproviding a chamber 21 into which the percussive-motor A exhausts. r T vf The working tool or drill bit B extends into the barrel ,10 of motor Ato receive the blows of hammer piston 14 and is preferably formed with acollar 6 which not only serves to limit the extent of the bit shankwithin the barrelbut also cooperates with a. retainer 22 secured to thefront end of cylinder 3 and of suflicient length to permit the movementof 3 motor A within cylinder 3. Cylinder 3 has a series of radialexhaust ports 23 in a plane substantiallycentrally of chamber 30.

Encircling the reduced portion or barrel 10 of the motor A and disposedwithin the annular chamber provided between the latter and the 'cylinder3 is) a coil spring 24 which bears against motor head 9 on the one handand cylinder ring 11 on the other and normally maintains motor Ainwardly of cylinder To prevent motor A from striking head 5' whendriven inwardlyby the action of spring 24, suitable buffer means. suchas a rubber annulusz25, may be providedin the rear end of ehamber 3a tobe contacted by motor head '18 and thereby limit. the rearwanl movementof motor A.

In operation the opening ofthrotlle valve 7 admits motive fluid to therear end of chamber 3a, the motive fluid innnediately becoming effectiveagainst the full area of motor head 18, with the result that motor A isdriven forwardly in cylinder 3 against spring 24 (or cylinder 3 isdriven rearwardly against such pressure as the operator may be applyingto handles 4). -When relative movement of motor A and cylinder 3 hasreached the point where exhaust ports 23 register with exhaust chamber21, percussive motor A goes into operation and con- Ell tinues inoperation so long as it can exhaust through ports 23. To this end it isnecessary that the operator apply sufficient pressure to handles .4 tobalance, with the assistance of spring 24, the air pressure uponbackhead 18 of the motor. When the throttle valve is closed and thepressure in the rearward end of chamber 3w vents to atmosphere throughmotor A, spring 24 moves motor A rearwardly or cylinder 3 downwardlyuntil the motor is in-inoperative position as disclosed in Fig. 1.

While a preferred form of the invention has been herein shoWn anddescribed, it is to be understood that the invention is not limited tothe specific details thereof, but

covers all changes, modifications, and adap-' tations within the scopeof the appended claims.

T claim as my invention:

1. A hand supported percussive tool comprising in combination a memberhaving a handle and providing an elongate chamber, a fluid pressurepercussive motor movable within said chamber, fluid pressure inlet meansin said member adjacent said handle, the admitted pressure fluid beingeffective first to move said motor forwardly in said chamber andthereafter to operate said motor, and means wholly independent of thepressure fluid for opposing forward movement of said motor and formovlng said motor rearwardly when the pressure fluid is no longeradmitted.

2. A hand supported percussive tool comprising in combination a memberhaving a handle and providing an elongate chamber, a fluid pressurepercussive motor movable within said chamber, fluid pressure inlet meansin said member adjacent said handle, the admitted pressure fluid belngeflt'ective first to move said motor forwardly in said chamber andthereafter to operate said motor, means wholly independent of thepressure fluid for opposing forward movement of said motor and formoving sa d motor rearwardly when the pressure fluid is no longeradmitted, and a resilient buffer for checking the rearward movement ofsaid motor.

3. A fluid pressure tool comprising a cylinder member having a T handleand means including a throttle valve on said member for controlling theadmission of pressure fluid to the chamber of said cylinder member, afluid pressure motor movable as aunit within said chamber in onedirection by.

the pressure fluid admitted thereto, means permitting operation of saidmotor by said admitted pressure fluid only when said motor is at acertain position within said cham her, and means for resisting movementof said motor by said pressure fluid and tending to maintain said motorat said certain operative position.

4. A fluid pressure tool comprising 8. cylinder member having a T handleand means including a throttle valve on said member for controlling theadmission of pressure fluid to the chamber of said cylinder member, afluid pressure motor movable as a unit within said chamber in onedirection by the pressure fluid admitted thereto, means permittingoperation of said motor by said ad- Initted pressure fluid only atcertain posit1ons of the latter in said chamber, said means includingone or more exhaust ports through said member, and means including asprin for resisting movement of said motor by said pressure fluidtending to maintain said motor at said certain operat1ve position.

5. A fluid pressure tool comprisin a cylinder member having a T handlean means including a throttle valve on said member for controlling theadmission of pressure fluid to the chamber of said cylinder member, afluid pressure motor movable as a unit within said chamber in onedirection by the pressure fluid admitted thereto, means permittingoperation of said motor by said admitted pressure fluid only when saidmotor is at a certain position within said chamber, and means whollyindependent of said admitted pressure fluid for resisting movement ofsaid motor by said pressure fluid and tending to maintain said motor atsaid certain operative position.

6. A fluid pressure tool comprising a cylinder member providing anelongate chamber and having a T handle, means including a throttle valveon said member for controlling the admission of pressure fluid to saidchamber, a fluid pressure motor movable as a unit in said chamber by thepressure fluid admitted thereto, means permittin operation of said motorby said pressure uid only at certain positions in said chamber includingradial ports through said member, and means wholl independent of thepressure fluid for resisting movement of said motor by the pressurefluid and for moving said motor to a non-operative position within saidchamber, said last named means comprising a coil spring encircling aportion of said motor within said chamber and arranged to be com ressedby the movement of said motor by t e pressure fluid.

Signed by me at New York, in the county of New York, and State of N. Y.this 31st day of March, 1928.

A. H. COLLINS.

